A heat exchanger is a device which effects the transfer of heat from one fluid to another. There are several basic types of heat exchangers in use today--the type described and disclosed herein is of the crossflow type as is used in automobile radiators to cool the fluid circulating through the engine block of a liquid cooled engine. In the crossflow type of heat exchanger two fluids (in this case ambient ram air and heated liquid) flow along the heat transfer surface at right angles (normal) to each other, where the heated liquid may flow in either a horizontal or vertical direction. The fluid flow takes place in spaces separated by a wall and heat is exchanged by convection at and conduction through the wall.
Current radiator designs employ several structural and fluid carrying elements. Therefore, the radiator reliability, expressed as a mean-time-between-failure (MTBF), will increase in direct proportion to the number of elements used. The most common time-induced failure modes are fluid leaks. These leaks most often occur at pressure points around the interfacing joint of the filler neck with the tank and at the interface of the radiator tubes with the tank header. Additionally, the tank seams are also subject to leaks. Most state-of-the-art tanks are joined by either a butt seam or a drop-down groove seam.
Using large quantities of components also affects cost effectiveness in terms of radiator manufacturing and assembly/selling costs. Additionally, the increased bulk and weight of the radiator increases fuel consumption, and more space must be allocated in the engine compartment to mount the radiator.
A search of the prior art did not disclose any patents that directly read on the instant invention. However, the following U.S. patents are considered related:
______________________________________ U.S. PAT. NO. INVENTOR ISSUE DATE ______________________________________ 3,246,691 LaPorte, et al 19 April 1966 3,310,868 LaPorte, et al 28 March 1967 ______________________________________
The two LaPorte patents disclose a cellular-tubular type of automotive radiator where the components are so related structurally that the radiator may be integrated in a single baking or solder melting operation with a minimum of handling and jigging.
In the later LaPorte patent the manufacturing process is improved by devising a method pre-stressing the radiator including the core mass by the sidewalls of the radiator which are devised as springs to compress the core mass at a constant rate.